Post-treatment impacts of a novel combined hydrogen peroxide (H2O2) oxidation and WOx/ZrO2 catalysis used for the removal of 1,4-dioxane and chlorinated volatile organic compound (CVOC) contaminants were investigated in soil and groundwater microbial community. This treatment train removed ~90% 1,4-dioxane regardless of initial concentrations of 1,4-dioxane and CVOCs. The Illumina Miseq platform and bioinformatics were used to study the changes to microbial community structure. This approach determined that dynamic shifts of microbiomes were associated with conditions specific to treatments as well as 1,4-dioxane and CVOCs mixtures. The biodiversity was observed to decrease only after oxidation under conditions that included high levels of 1,4-dioxane and CVOCs, but increased when 1,4-dioxane was present without CVOCs. WOx/ZrO2 catalysis reduced biodiversity across all conditions. Taxonomic classification demonstrated oxidative tolerance for members of the genera Massilia and Rhodococcus, while catalyst tolerance was observed for members of the genera Sphingomonas and Devosia. Linear discriminant analysis effect size was a useful statistical tool to highlight representative microbes, while the multidimensional analysis elucidated the separation of microbiomes under the low 1,4-dioxane-only condition from all other conditions containing CVOCs, as well as the differences of microbial population among original, post-oxidation, and post-catalysis states. The results of this study enhance our understanding of microbial community responses to a promising chemical treatment train, and the metagenomic analysis will help practitioners predict the microbial community status during the post-treatment period, which may have consequences for long-term management strategies that include additional biodegradation treatment or natural attenuation.
Studies of avian eggshell coloration have been a long-standing research focus in behavioral evolutionary ecology. Museum collections
have provided a widely used resource because they allow efficient sampling across broad temporal, geographical, and taxonomic
ranges, even for species that are rare and for which sampling in the wild is ethically or practically unwarranted. We used
reflectance spectrophotometry across the avian visual spectrum to compare eggshell color of specimens of the song thrush (Turdus philomelos) in two museums (Natural History Museum, UK and Auckland Museum, New Zealand) with each other and with eggshells collected
fresh in New Zealand. These data enabled us to test the effects of source and storage in different museums, as well as time
since collection, across four metrics of eggshell coloration: blue-green and ultraviolet chroma, overall brightness, and the
spectral coefficient of variation. Variation within an egg, within a clutch, and among clutches, was similar between the two
museum datasets but different from those of fresh eggs. We found significant differences in all four metrics between the collections,
and that fresh eggshells reflected stronger in the blue-green wavelength than in museum eggs. This difference is most likely
due to different preservation techniques and storage histories. Furthermore, an effect of time since collection was only apparent
in the blue-green chroma and was higher in more recent museum eggshell samples. Our results support the use of historic museum
samples in intraspecific studies of shell coloration providing that efforts are made to compare specimens, which were collected
during similar periods. 相似文献
This paper describes the results of the first stage of Phase III of a Joint Industry Project (JIP) on liquid jets and two-phase droplet dispersion. This stage included scaled experiments for water, gasoline, and cyclohexane for a range of superheats and nozzles with different aspect ratios. Additional experiments for butane and propane were conducted as a validation exercise and are discussed in the companion paper. Moreover this paper provides recommendations for atomisation correlations in the regimes of mechanical break-up, transition to flashing, and fully flashing. The objectives of this scaled experimental programme are to : (i) provide confidence in the previously proposed modelling methodology (Phase II) across a broad range of initial conditions (ii) update the models’ correlations to generalise further its applicability (iii) recommend further model improvements. Development of new correlations for Sauter Mean Droplet diameter (SMD) and droplet size distribution is based on a best fit of the current scaled experimental data. The new data endorses the previous tri-functional Phase II approach including regimes for mechanical break-up, transition to flashing, and fully flashing, which is hence updated in the new Phase III SMD model. Considerable effort is devoted to capturing the full droplet size range under low-superheat conditions. Also, new enhancements in PDA technology were adopted to enable better quality data under high-superheat conditions. The priority recommendation for further model improvement is better characterisation of the poor quality releases under low-superheat conditions, where this work indicates that extremely broad droplet size distributions are likely. A companion paper (Part I) presents a more general overview of the dispersion problem, implementation of the correlations and subsequent performance against both the current scaled experiments and additional large-scale butane experiments. 相似文献
Wastewater discharge from sugarcane processing is a significant pollutant of tropical aquatic ecosystems. For most developing countries, monitoring of the level of pollutants is done mostly through chemical analysis, but this does not reflect potential impacts on aquatic assemblages. In addition, laboratory facilities for accurate concentration measurements are often not available for regular monitoring programs. In this study, we investigated the use of benthic macroinvertebrates for biological monitoring in western Kenya. Benthic macroinvertebrates were sampled in stabilization ponds treating wastewater from sugarcane- and molasses-based processing plants to assess their composition and abundance in relation to different concentrations of chemical variables. Optimum concentrations and tolerance values were identified for various taxa, and a biotic index was developed that combined tolerance values (ranked between 0 and 10) for the various macroinvertebrate taxa. A succession in composition and distribution of macroinvertebrate taxa was observed from the inlet to the outlet of the pond systems. Diptera dominated in the first ponds that had high concentrations of chemical oxygen demand (COD), biological oxygen demand (BOD5), and nutrients, while intolerant Ephemeroptera, Plecoptera, and Trichoptera (EPT) appeared as the concentrations dropped in subsequent ponds. The effluent quality was classified as “good,” “fair,” and “poor,” corresponding with biotic index value ranges 0–3.50, 3.51–6.50, and 6.51–10, respectively. During validation, the index grouped sites with respect to levels of measured environmental variables. The study revealed that the developed biotic index would help in monitoring the quality of sugarcane processing and molasses effluents before release into recipient aquatic ecosystems, replacing the need for costly chemical analyses. 相似文献
Following the remediation of animal manure spills that reach surface waters, contaminated streambed sediments are often left in place and become a source for internal phosphorus (P) loading within the stream in subsequent flow. The objective of this study was to develop treatment rates and combinations of alum and CaCO(3) to mitigate P from contaminated sediments of different particle size distributions following a manure spill. Sediment specific alum and CaCO(3) treatment rates were developed based upon the resultant alum treatment ranges established for each sediment type. Clay loam sediments required 54% more alum to mitigate P desorption relative to sediments that contain at least 60% sand. Amending sediments with the highest rates of alum/alum + CaCO(3), resulted in a 98-100% reduction in P desorption and a similar water column pH for all sediments types. Observations from this study demonstrated the effectiveness of alum/alum + CaCO(3) to increase P retention in sediments following a manure spill. 相似文献
In birds, the position and extent of the region of binocular vision appears to be determined by feeding ecology. Of prime
importance is the degree to which vision is used for the precise control of bill position when pecking or lunging at prey.
In birds that do not require such precision (probe and filter-feeders), the bill falls outside the binocular field, which
extends above and behind the head, thus providing comprehensive visual coverage. Flamingos Phoenicopteridae are highly specialised
filter-feeders. They employ a unique technique that does not require accurate bill positioning in which the inverted head
is placed between the feet. Feeding flamingos often walk forwards with the head pointing “backwards”. Here we show that in
Lesser Flamingos Phoeniconaias minor visual fields are in fact the same as those of birds that feed by precision pecking and that feeding flamingos are blind
in the direction of their walking. We suggest that this is due to the requirement for accurate bill placement when flamingos
feed their chicks with “crop-milk”, and possibly when building their nest. We propose that chick-feeding may be the ultimate
determinant of visual field topography in birds, not feeding ecology. 相似文献